1. Field of the Invention
The present invention relates to an airbag made of flexible woven cloth with an external wall.
2. Description of Related Art
In the related art, as an airbag, there is that shown in Japanese Patent Unexamined Publication No. 10-129380. With such an airbag, a bag was made by respectively applying unvulcanized rubber, thermoplastic polyurethane, and the like that are a coating layer for preventing gas leakage over the entire surfaces of two base cloths that compose an external wall, and adhering the outer peripheries of each of the two base cloths by cure adhesion or heat sealing.
With such an airbag of the related art, the thickness of the thread that configures a base cloth is not specified. However, in case of adhering a thick thread base cloth to a fine thread base cloth with threads of different thicknesses, it is difficult to obtain a favorable adhesion strength. The reason is that the convexities and concavities on the adhesion faces of the two differ by the difference in the thicknesses of the threads. In particular, in case of adhering two base cloths by providing a coating layer on only one of the base cloths and fusing the coating layer by overlapping the other base cloth on the coating layer, it is difficult to obtain a favorable adhesion strength with base cloths with threads of different thicknesses. Therefore, in case that base cloths with threads of different thicknesses to each other are used, a coating layer is provided on only one of the base cloths, and the other base cloth is adhered, there was scope for improvement in raising the adhesion strength.